One type of precipitation hardening copper alloy is the copper-nickel-silicon alloy with a nominal 2% nickel, 0.45% silicon and remainder copper. This alloy combines excellent stress relaxation resistance with high strength and high conductivity. The combination of strength, formability and conductivity is reached through a thermo-mechanical process combining cold deformation and heat treatments.
In order to obtain high electrical conductivity, it is necessary to have a high degree of precipitation of the alloy elements. The size and fraction of the precipitates are also important for the resulting microstructure and consequently for the mechanical properties. A dispersion of fine precipitates can retard recrystallization or hinder grain growth and also increase the strength. Depending on the size and amount of precipitates, different combinations of properties are achieved.